Answer: D. Proteins
Background Info: (from Wikipedia)
A biomolecule or biological molecule is a loosely used term for molecules and ions that are present in organisms, essential to some typically biological process such as cell division, morphogenesis, or development.[1] Biomolecules include large macromolecules (or polyanions) such as proteins, carbohydrates, lipids, and nucleic acids, as well as small molecules such as primary metabolites, secondary metabolites, and natural products. A more general name for this class of material is biological materials. Biomolecules are usually endogenous but may also be exogenous. For example, pharmaceutical drugs may be natural products or semisynthetic (biopharmaceuticals) or they may be totally synthetic.
